graphmod: correctly emit nodes with more than 2 predecessors The grandparent() function was returning only the closest predecessor of a missing parent while it must return all of them to display a correct ancestry graph.

graphlog: display nodes with more than 2 predecessors While nodes with more than 2 parents do not exist in revision graphs, they do appear when you transform them by removing subgraphs while trying to preserve ancestry links. This code was borrowed from Peter Arrenbrecht <peter.arrenbrecht@gmail.com> pbranch extension.

context: provide an efficient iterator for workingctx This avoids needing to call status or build a synthetic manifest.

merge with stable